A258959 Number of (n+2) X (1+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.

66, 158, 214, 462, 676, 1374, 2040, 4104, 6136, 12296, 18424, 36872, 55288, 110600, 165880, 331784, 497656, 995336, 1492984, 2985992, 4478968, 8957960, 13436920, 26873864, 40310776, 80621576, 120932344, 241864712, 362797048, 725594120

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = -a(n-1) + 3*a(n-2) + 3*a(n-3) for n>9.

Empirical g.f.: 2*x*(33 + 112*x + 87*x^2 + 2*x^3 + 11*x^4 + 11*x^5 - 3*x^7 - x^8) / ((1 + x)*(1 - 3*x^2)). - Colin Barker, Dec 23 2018

Example

Some solutions for n=4:
..1..1..0....1..0..1....0..0..1....0..0..1....1..0..1....0..1..1....0..1..0
..1..0..0....1..1..0....1..0..0....1..1..0....1..1..0....1..0..0....1..0..1
..0..1..1....0..0..1....0..1..1....0..1..0....0..1..0....0..0..1....1..0..1
..1..0..0....1..0..0....1..0..0....1..0..1....1..0..1....1..1..0....0..1..0
..0..1..1....0..1..1....0..1..1....0..0..1....1..0..1....0..1..0....0..1..1
..0..0..1....1..0..0....0..1..1....0..1..0....0..1..0....0..0..1....1..0..0

Crossrefs

Column 1 of A258966.

Sequence in context: A278783 A358102 A258966 * A062035 A043514 A044398

Adjacent sequences: A258956 A258957 A258958 * A258960 A258961 A258962

Keyword

nonn

Author

R. H. Hardin, Jun 15 2015

Status

approved